Conventional multi-pane insulating glass assemblies generally have two substantially parallel, spaced apart panes which are separated by a peripheral spacer. The spacers commonly are formed metal tubes constructed so as to have two flat, substantially parallel sides facing the interior surfaces of the panes. The interior surfaces of the panes are bonded to the sides of the spacer by a sealant material such as polyisobutelyne. To enhance the thermal resistance across such glass assemblies, the interpane space between the panes is filled with an insulating gas having a thermal conductivity that is less than that of air.
Glass assemblies are generally either uniform production line assemblies or custom made assemblies. Uniform production line glass assemblies are made in large quantities and all of the assemblies have the same size and shape. Because of the repetition involved in making uniform glass assemblies, it is generally cost effective to develop specific manufacturing assembly lines to manufacture large quantities of a single type glass assembly. Custom assemblies, on the other hand, are generally manufactured in very small quantities as low as a single assembly, and each assembly may have a unique size and shape.
The interpane space of a multi-pane glass assembly is filled with an insulating gas by drawing a vacuum to remove the air within the interpane space before both panes are sealed to the spacer, and then replacing the air with an insulating gas such as argon. After the interpane space is filled with an insulating gas, the panes are sealed to the spacer so that the gas does not escape into the atmosphere.
Several methods and apparatuses exist for assembling and replacing the air in a plurality of uniform glass assemblies. One method is disclosed in U.S. Pat. No. 5,017,252, entitled METHOD FOR FABRICATING INSULATING GLASS ASSEMBLIES, and another method and apparatus is disclosed in U.S. Pat. No. 4,780, 164, entitled METHOD FOR PRODUCING GAS-CONTAINING INSULATING GLASS ASSEMBLIES, the disclosures of which are herein incorporated by reference. Several uniform glass assemblies may be simultaneously filled with gas in a single gas exchange cycle because the uniformity of the assemblies allows them to be arranged adjacent to one another so that the spacers are aligned with one another. The panes of each assembly are compressed against the adhesive on the spacer under either the weight of the adjacent assemblies or by a single hydraulically actuated platen. By arranging the assemblies so that the spacers are aligned with one another, the compressive forces are borne by the spacers and the glass aligned with the spacers. Accordingly, the only portions of the panes of a uniform glass assembly that bear any loading are those that are supported by the spacers. Yet, when custom glass assemblies are arranged in the same manner, there will be an unsupported portion in the larger of two adjacent panes because the spacers cannot be aligned. As such, conventional methods and devices for filling a plurality of uniform gas assemblies are not useful for filling custom glass assemblies.
Another device for assembling and filling glass assemblies one at a time is disclosed in European Patent No. 0 056 762. The device disclosed in European Patent No. 0 056 762 includes a series of rollers inclined at an angle and an inclined surface which provides an air bearing to transport a single pane of glass and a spacer into a gas exchange chamber. The gas exchange chamber has a pivoting platen which carries the second pane. The first pane and spacer are moved into the chamber opposite the platen, and after an insulating gas has been exchanged for the air in the chamber, the second pane is pressed against the spacer to seal the interpane space between the panes. The device shown European Patent No. 0 056 762 does not adequately seal custom glass assemblies having spacers of different widths without requiring significant adjustments of the pivoting platen. Moreover, it is difficult to properly align the first and second panes of custom glass assemblies in the device shown European Patent No. 0 056 762 because at least one of the panes is fixed to the platen before it is pressed against the spacer. As such, the other pane must be positioned on the rollers and the air bearing without knowing the precise alignment with the pane carried by the spacer. Because of the difficulty in aligning the panes, it would appear that experimentation is required to use the device discussed in European Patent No. 0 056762 to properly align the panes of a custom glass assembly.
It would be advantageous to provide a method and apparatus for quickly assembling a small number of custom insulating glass assemblies and filling such glass assemblies with an insulating gas.